1. Field of the Invention
The present invention relates to a radio frequency (RF) electrostatic discharge (ESD) protection circuit, especially to a V-band (50-75 GHz) RF ESD protection circuit which uses a meander inductor and an ESD member connecting in series for protecting a core circuit from ESD.
2. The Prior Arts
In a communication system or a sub-circuit of the communication system, such as a low-noise amplifier (LNA), the input port thereof directly contacts with external environment through an antenna. Thus, the circuit is likely to be damaged by static electricity due to environment, weather, or human factors. At the present day, the technology to protect the system at a direct current bias port from electrostatic damage is pretty mature. However, an electrostatic protection circuit to protect the system will generate a stray effect. The electrostatic protection at an RF input port or an RF output port is still a challenge due to the stray effect of the electrostatic protection circuit itself.
As communication systems progress, electronic products with high data transmission rates have been developed and therefore the operation frequencies also increase. When operated in high frequency, the stray effect of the conventional electrostatic protection circuit will seriously degrade the performance of a core circuit. Although various RF electrostatic protection designs are disclosed to minimize the performance degradation of the core circuits caused by the protection circuits, the designs in the millimeter wave range still pose many problems.